Precise Regulation of Zn, S Dual Vacancies in Zn ₃ In ₂ S ₆ Inducing Local Orientated Electrical Field for Photocatalytic H ₂ O ₂ Generation

Abstract Photocatalytic H 2 O 2 synthesis attracts interest for solar‐to‐fuel conversion but suffers from low carrier utilization and sluggish kinetics. Herein, we present a confinement strategy to precisely regulate Zn and S vacancies (V Zn , V S ) in Zn 3 In 2 S 6 for photocatalytic H 2 O 2 generation. ZnSO 4 , InCl 3 , thioacetamide, and cetyltrimethylammonium bromide (CTAB) were utilized to synthesize Zn 3 In 2 S 6 via a hydrothermal process, in which CTAB inserts into anionic layers and forms covalent bonds with Zn 2+ ions, then pyrolyzes and removes Zn 2+ ions during the annealing process, inducing V Zn formation. H 2 ‐mediated desulfurization generates V S . The contents of V Zn and V S in Zn 3 In 2 S 6 of 1.9:1.0, 1.1:1.0, 1.0:1.9, and 1.0:3.3 were obtained by adjusting the temperature. V S &V Zn ‐Zn 3 In 2 S 6 (1.0:1.9) exhibits a fantastic photocatalytic generation rate of 11580.74 µmol g −1 h −1 for H 2 O 2 which increased 2.4 times compared with V S ‐Zn 3 In 2 S 6 , attributing to that dual vacancies promote the local orientated electrical field (LOEF) formation and increase photogenerated‐electron transfer from V S to V Zn . Electrons delocalize onto adjacent Zn sites, promoting the two‐electron oxygen reduction reaction (ORR) pathway. Simultaneously, V Zn facilitates the migration of h⁺ to the catalyst surface, thereby increasing h⁺ utilization efficiency and accelerating the water oxidation reaction (WOR) process toward H 2 O 2 production. V S &V Cu ‐CuIn 2 S 4 and V S &V Ni ‐NiIn 2 S 4 were successfully synthesized, highlighting its broad applicability as a general approach.